PROJECT SUMMARY Hospital readmissions are associated with significant morbidity, mortality, and cost among older adults with heart failure. Despite advances in medical therapy and increased focus on improving care transitions, readmission rates for older adults hospitalized with heart failure remain unacceptably high, underscoring the importance of identifying novel modifiable factors that influence 30-day readmissions. Polypharmacy may represent an overlooked modifiable factor that impacts readmission rates. Broadly defined as the use of more medications than are medically necessary, polypharmacy is associated with a myriad of adverse outcomes including falls, disability, and hospitalizations. Yet, the impact of polypharmacy on readmissions among older adults hospitalized for heart failure has not been examined. Specific aims of this proposal are to: 1) describe discharge medication prescribing patterns among older adults following a heart failure hospitalization, including potentially inappropriate medications defined by the 2015 Updated Beers criteria; and 2) test the association of the number of total medications and presence of potentially inappropriate medications with 30- and 90-day all- cause readmission following a heart failure hospitalization. These aims will be achieved by examining a population-based prospective cohort of community-dwelling adults (REasons for Geographic And Racial Differences in Stroke [REGARDS] cohort), which is particularly well-suited for this investigation given its geographic and cultural diversity, unselected population, rigorous adjudication process to classify heart failure hospitalizations, established link to Medicare claims data, and the unique availability of hospital records for review and abstraction. This project will be conducted under the mentorship of 3 well-funded active K24 recipients who will bring their expertise in Geriatrics (Mark Lachs, MD, MPH), Cardiology (Mathew Maurer, MD), and Epidemiology (Monika Safford, MD) to this project. This mentorship combined with carefully selected advisors who will provide additional expertise in geriatric pharmacology (Joseph Hanlon, PharmD), inferential statistics (Ivan Diaz, PhD), and Medicare data (Emily Levitan, ScD) will further enhance both the success of the proposed study as well as the career development of the applicant. The applicant, Dr. Parag Goyal MD, is a cardiologist with advanced heart failure training and a deep commitment to caring for the geriatric population. With this R03 proposal, Dr. Goyal hopes to build upon his prior work to address an important gap in the literature and develop the skills and knowledge necessary to improve post-hospitalization outcomes among older adults with heart failure. Specifically, this R03 will help Dr. Goyal develop preliminary data and acquire critical skills in analyzing large epidemiologic studies, geriatric pharmaco-epidemiology, and inferential statistics, which will help inform the design of a future study and proposal for an NIH career development award aimed at intervention development. It will also facilitate Dr. Goyal's ultimate development into a leader and independently-funded clinical investigator in geriatric cardiology.